1. Field of the Invention
The present invention relates to a probe apparatus, and more particularly to a probe apparatus having a mechanism for cleaning probe needles used to check the electrical characteristics of an object to be examined.
2. Description of the Related Art
In general, a probe apparatus for checking the electrical characteristics of an object to be examined has a mount, which can be moved vertically and horizontally and can be rotated in a horizontal plane, and a probe card including a large number of probes which are brought into contact with the electrodes formed on the object to be examined, such as a semiconductor wafer. The probe needles are affixed to the probe card such that they are inclined at a predetermined angle with respect to the probe card. The mount is moved to a predetermined position, and the probe needles are brought into contact with the electrode pads formed on the object to be examined which is placed on the mount, thus checking the electrical characteristics of the semiconductor wafer.
In recent years, the arrangement of electrode pads has become more and more complicated owing to the increasing complexity and microminiaturization of semiconductor devices, making it difficult for the inclined probe needles to accurately contact the electrode pads. In consideration of this, a method has been devised wherein probe needles, known as vertical probe needles which are arranged so as to extend vertically, are brought into contact with complexly arranged electrode pads. The vertical probe needles can accurately contact the electrode pads at uniform pressure.
Using the vertical probe needles, the electrical characteristics of the object to be examined can be measured accurately. However, there are cases where accurate measurements cannot be performed due to the following situation:
In general, probe needles are designed such that when they come into contact with the oxide films applied over aluminum electrode pads on a semiconductor wafer, they scratch the oxide films in order to attain electrical connection with the electrode pads. Especially in the case of vertical probe needles, aluminum waste easily adheres to the tips thereof. As the examination process is repeatedly performed, more and more aluminum waste is deposited on the tips, preventing the vertical probe needles from being electrically connected to the electrode pads, with the result that accurate measurements cannot be attained. The aluminum waste A deposited also shortens the life of the vertical probe needles. In addition, if the aluminum waste falls on the semiconductor wafer in the form of particles, it may degrade the quality of the semiconductor wafer.